Use gdb:array_view in call_function_by_hand & friends

This replaces a few uses of pointer+length with gdb::array_view, in
call_function_by_hand and related code.

Unfortunately, due to -Wnarrowing, there are places where we can't
brace-initialize an gdb::array_view without an ugly-ish cast.  To
avoid the cast, this patch introduces a gdb::make_array_view function.
Unit tests included.

This patch in isolation may not look so interesting, due to
gdb::make_array_view uses, but I think it's still worth it.  Some of
the gdb::make_array_view calls disappear down the series, and others
could be eliminated with more (non-trivial) gdb::array_view
detangling/conversion (e.g. code around eval_call).  See this as a "we
have to start somewhere" patch.

gdb/ChangeLog:
2018-11-21  Pedro Alves  <palves@redhat.com>

	* ada-lang.c (ada_evaluate_subexp): Adjust to pass an array_view.
	* common/array-view.h (make_array_view): New.
	* compile/compile-object-run.c (compile_object_run): Adjust to
	pass an array_view.
	* elfread.c (elf_gnu_ifunc_resolve_addr): Adjust.
	* eval.c (eval_call): Adjust to pass an array_view.
	(evaluate_subexp_standard): Adjust to pass an array_view.
	* gcore.c (call_target_sbrk): Adjust to pass an array_view.
	* guile/scm-value.c (gdbscm_value_call): Likewise.
	* infcall.c (push_dummy_code): Replace pointer + size parameters
	with an array_view parameter.
	(call_function_by_hand, call_function_by_hand_dummy): Likewise and
	adjust.
	* infcall.h: Include "common/array-view.h".
	(call_function_by_hand, call_function_by_hand_dummy): Replace
	pointer + size parameters with an array_view parameter.
	* linux-fork.c (inferior_call_waitpid): Adjust to use array_view.
	* linux-tdep.c (linux_infcall_mmap): Likewise.
	* objc-lang.c (lookup_objc_class, lookup_child_selector)
	(value_nsstring, print_object_command): Likewise.
	* python/py-value.c (valpy_call): Likewise.
	* rust-lang.c (rust_evaluate_funcall): Likewise.
	* spu-tdep.c (flush_ea_cache): Likewise.
	* valarith.c (value_x_binop, value_x_unop): Likewise.
	* valops.c (value_allocate_space_in_inferior): Likewise.
	* unittests/array-view-selftests.c (run_tests): Add
	gdb::make_array_view test.

1 files changed, 9 insertions, 9 deletions

diff --git a/gdb/eval.c b/gdb/eval.c
index 047aba5..6eb210d 100644
--- a/gdb/eval.c
+++ b/gdb/eval.c
@@ -830,7 +830,7 @@ eval_call (expression *exp, enum noside noside,
       return call_xmethod (argvec[0], nargs, argvec + 1);
     default:
       return call_function_by_hand (argvec[0], default_return_type,
-				    nargs, argvec + 1);
+				    gdb::make_array_view (argvec + 1, nargs));
     }
 }
 
@@ -1728,12 +1728,12 @@ evaluate_subexp_standard (struct type *expect_type,
 	argvec[3] = value_from_longest (long_type, selector);
 	argvec[4] = 0;
 
-	ret = call_function_by_hand (argvec[0], NULL, 3, argvec + 1);
+	ret = call_function_by_hand (argvec[0], NULL, {argvec + 1, 3});
 	if (gnu_runtime)
 	  {
 	    /* Function objc_msg_lookup returns a pointer.  */
 	    argvec[0] = ret;
-	    ret = call_function_by_hand (argvec[0], NULL, 3, argvec + 1);
+	    ret = call_function_by_hand (argvec[0], NULL, {argvec + 1, 3});
 	  }
 	if (value_as_long (ret) == 0)
 	  error (_("Target does not respond to this message selector."));
@@ -1750,11 +1750,11 @@ evaluate_subexp_standard (struct type *expect_type,
 	argvec[3] = value_from_longest (long_type, selector);
 	argvec[4] = 0;
 
-	ret = call_function_by_hand (argvec[0], NULL, 3, argvec + 1);
+	ret = call_function_by_hand (argvec[0], NULL, {argvec + 1, 3});
 	if (gnu_runtime)
 	  {
 	    argvec[0] = ret;
-	    ret = call_function_by_hand (argvec[0], NULL, 3, argvec + 1);
+	    ret = call_function_by_hand (argvec[0], NULL, {argvec + 1, 3});
 	  }
 
 	/* ret should now be the selector.  */
@@ -1890,17 +1890,17 @@ evaluate_subexp_standard (struct type *expect_type,
 	  argvec[tem + 3] = evaluate_subexp_with_coercion (exp, pos, noside);
 	argvec[tem + 3] = 0;
 
+	auto call_args = gdb::make_array_view (argvec + 1, nargs + 2);
+
 	if (gnu_runtime && (method != NULL))
 	  {
 	    /* Function objc_msg_lookup returns a pointer.  */
 	    deprecated_set_value_type (argvec[0],
 				       lookup_pointer_type (lookup_function_type (value_type (argvec[0]))));
-	    argvec[0]
-	      = call_function_by_hand (argvec[0], NULL, nargs + 2, argvec + 1);
+	    argvec[0] = call_function_by_hand (argvec[0], NULL, call_args);
 	  }
 
-	ret = call_function_by_hand (argvec[0], NULL, nargs + 2, argvec + 1);
-	return ret;
+	return call_function_by_hand (argvec[0], NULL, call_args);
       }
       break;